Filter with improved hardness and filtration efficiency

ABSTRACT

There is provided a smoking article comprising an aerosol generating substrate and a mouthpiece attached to the aerosol generating substrate. The mouthpiece includes a segment comprising a filtration material comprising polylactic acid, and an additive for reducing phenols. The mouthpiece further comprises one or more wrappers circumscribing the segment, the one or more wrappers have a combined basis weight of at least about 50 grams per square metre (gm- 2 ).

The present invention relates to a mouthpiece for a smoking article,comprising polylactic acid, and to a smoking article incorporating sucha mouthpiece.

Filter cigarettes typically comprise a rod of tobacco cut fillersurrounded by a paper wrapper and a cylindrical filter aligned inend-to-end relationship with the wrapped tobacco rod, with the filterattached to the tobacco rod by tipping paper. In conventional filtercigarettes, the filter may consist of a plug of cellulose acetate towwrapped in porous plug wrap. Filter cigarettes with multi-componentfilters that comprise two or more segments of filtration material forthe removal of particulate and gaseous components of the mainstreamsmoke are also known.

A number of smoking articles in which an aerosol forming substrate, suchas tobacco, is heated rather than combusted have also been proposed inthe art. In heated smoking articles, the aerosol is generated by heatingthe aerosol forming substrate. Known heated smoking articles include,for example, smoking articles in which an aerosol is generated byelectrical heating or by the transfer of heat from a combustible fuelelement or heat source to an aerosol forming substrate. During smoking,volatile compounds are released from the aerosol forming substrate byheat transfer from the heat source and entrained in air drawn throughthe smoking article. As the released compounds cool, they condense toform an aerosol that is inhaled by the consumer. Also known are smokingarticles in which a nicotine-containing aerosol is generated from atobacco material, tobacco extract, or other nicotine source, withoutcombustion, and in some cases without heating, for example through achemical reaction.

After a smoking article has been smoked and the remainder of the articlehas been discarded, it is often desirable for the remainder of thearticle to degrade as quickly as possible. It has therefore beenproposed to form portions of a smoking article, such as filters, frommaterials than are more degradable than those materials conventionallyused for such portions. For example, it has been proposed to wholly orpartially replace the cellulose acetate in a filter with polylacticacid, as polylactic acid tends to be more degradable than celluloseacetate.

However, cellulose acetate can directly or indirectly provide certaindesirable properties for a filter, which are not as readily obtainablewhen the cellulose acetate of a filter is replaced with polylactic acid.For example, in conventional smoking articles, cellulose acetate fibresare typically sprayed with a triacetin additive. This can have two maineffects on the filter. Firstly, the triacetin can bond adjacent fibresto provide a desired firmness for the filter. Secondly, the triacetincan improve the filtration of smoke constituents, such as phenols, fromthe smoke drawn through the filter. There is no known additive, whichcan perform both these functions when sprayed on polylactic acid fibres.At least two separate additives are therefore needed for a polylacticacid based filter, in order for it to replicate these desirable featuresof a cellulose acetate based filter. This can add complexity to themanufacturing process and may also require modification of existingmachinery.

Therefore, despite the perceived degradation benefits for filterscontaining polylactic acid, there is currently not a commerciallyacceptable solution for using polylactic acid as a filtration materialin a mouthpiece for a smoking.

According to a first aspect of the present invention, there is provideda smoking article comprising an aerosol generating substrate and amouthpiece attached to the aerosol generating substrate. The mouthpieceincludes a segment comprising a filtration material comprisingpolylactic acid, and an additive for reducing phenols. The mouthpiecefurther comprises one or more wrappers circumscribing the segment, theone or more wrappers have a combined basis weight of at least about 50grams per square metre (gm⁻²).

According to a second aspect of the present invention, there is provideda mouthpiece for a smoking article. The mouthpiece includes a segmentcomprising a filtration material comprising polylactic acid, and anadditive for reducing phenols. The mouthpiece further comprises one ormore wrappers circumscribing the segment, the one or more wrappers havea combined basis weight of at least about 50 grams per square metre(gm⁻²).

By circumscribing the segment with one or more wrappers have a combinedbasis weight of at least about 50 grams per square metre (gm⁻²), adesired firmness for the mouthpiece may be achieved. This firmness maybe comparable to the firmness that would otherwise have been provided bythe combination of cellulose acetate and triacetin in a conventionalsmoking article mouthpiece. The wrappers may be manufactured andprovided around the segment in accordance with standard techniques.

Furthermore, since the one or more wrappers may enable the mouthpiece tohave a desired firmness, there is no need for a second additive to beincluded in the mouthpiece in order to plasticize the filtrationmaterial. This means that the segment can be manufactured withoutmodifying existing techniques or machinery. For example, if anadditional additive was needed in order to provide firmness to thefiltration material, a second spraying station could be needed for thefilter manufacturing apparatus. This may require modification toexisting machinery and may also require additional cleaning of parts ofthe machinery, such as the garniture tongue, resulting in undesirabledowntime.

The inclusion of an additive for reducing phenols in the segment canhelp to reduce phenol levels delivered by the smoking article. Thisadditive may be incorporated into the segment using a spraying station,which is typically used on existing machinery for incorporating aconventional additive, such as triacetin, into a conventional filtersegment, such as one formed of cellulose acetate fibres.

Therefore, the present invention provides for a mouthpiece thatincorporates polylactic acid as a filtration material, withoutsacrificing the firmness or phenol reducing capabilities that aretypically associated with a conventional smoking article, and withoutneeding to alter the machinery or processes that are typically used tomanufacture such smoking articles.

The segment includes a filtration material comprising polylactic acid.The filtration material may have any suitable structure. For example,the filtration material may comprise a gathered sheet of materialcomprising polylactic acid. However, preferably the filtration materialcomprises a plurality of fibres formed at least in part from polylacticacid. Fibres are a particularly effective form of filtration material asthey can provide tortuous passageways through which smoke can pass.Furthermore, when a smoking article is discarded after use, the fibresmay degrade and disperse more readily than other structures, thushelping to improve the degradation properties of the mouthpiece orsmoking article.

Preferably, the fibres are substantially unconnected to one another.That is, preferably no additive is included in the segment for bindingthe fibres together. This can help to improve the rate at which thefibres can degrade and disperse when a smoking article is discardedafter use.

Preferably, the filtration material is a blend comprising polylacticacid and at least one other polymer. The additional polymer or polymersmay provide additional properties to the filtration material. Forexample, the additional polymers can provide the filtration materialwith additional tensile strength and elasticity properties. Where thefiltration material comprises a plurality of fibres made of a blend ofdifferent polymers, this can enable the fibres to be processed on thesame machinery that is typically used for manufacture of celluloseacetate filters, at a speed typically associated with the manufacture ofcellulose acetate filters, and with a comparable waste percentage andoperational efficiency.

Therefore, preferably, the filtration material is a blend comprisingpolylactic acid blended with at least one of polyglicolic acid andpoly-(L)-lactic acid. More preferably, the filtration material is ablend comprising polylactic acid, polyglicolic acid and poly-(L)-lacticacid. Such blends can result in a filtration material with desirabletensile strength and elasticity properties.

Preferably the filtration material comprises at least about 70%polylactic acid by weight, more preferably at least about 80% polylacticacid by weight, and even more preferably about 85% polylactic acid byweight.

Preferably the filtration material comprises less than about 20%polyglicolic acid by weight, more preferably less than about 15%polyglicolic acid by weight, and even more preferably about 10%polyglicolic acid by weight.

Preferably the filtration material comprises less than about 15%poly-(L)-lactic acid by weight, more preferably less than about 10%poly-(L)-lactic acid by weight, and even more preferably about 5%poly-(L)-lactic acid by weight.

In preferred embodiments the filtration material comprises a blendcomprising about 85% by weight polylactic acid, about 10% by weightpolyglicolic acid, and about 5% by weight poly-(L)-lactic acid.

As noted above, the segment comprising polylactic acid, also includes anadditive for reducing phenols. That is, the segment includes an additivewhich is capable of capturing or otherwise converting at least some ofthe phenols produced by the smoking article.

Preferably, the additive does not bond elements of the filtrationmaterial together.

Preferably, the additive comprises at least one of triacetin, triethylcitrate (TEC), polyethylene glycol, a mixture of triacetin withcellulose acetate flakes, or any combination thereof.

One particularly preferred additive is an additive comprising a mixtureof at least about 90% triacetin and less than about 10% celluloseacetate flakes, more preferably between about 96% and about 98%triacetin and between about 2% and about 4% cellulose acetate flakes.Such additives can be particularly desirable, as they can replicate thesynergy between triacetin and cellulose acetate fibres in a standardcellulose acetate filter.

Another preferred additive is low-molecular-weight glycols, such aspolyethylene or polyprophylene based glycols having a molecular weigthbetween about 100 and about 1000, more preferably between about 200 andabout 800, even more preferably between about 300 and about 500. In onepreferred embodiment, the additive is polyethylene glycol 400 (PEG 400).

Another preferred additive is triethyl citrate. As can be seen fromTable 2 below, such an additive can be particularly effective atreducing phenols.

Preferably, the additive is a transparent liquid with no odor or taste.Preferably, the additive has a viscosity that is the same as or greaterthan the viscosity of triacetin. This can allow the additive to be addedto the filtration material using the techniques and equipment normallyused for applying triacetin to standard cellulose acetate filters.

Preferably, the additive is provided in an amount of at least about 0.1percent by weight of the filtration material, more preferably at leastabout 5 percent by weight of the filtration material. Alternatively oradditionally, the additive is preferably provided in an amount of lessthan about 15 percent by weight of the filtration material, morepreferably less than about 12 percent by weight of the filtrationmaterial, even more preferably less than about 7 percent by weight ofthe filtration material.

Preferably the additive for reducing phenols is the only additiveincluded in the segment. This can allow the segment to be manufacturedwithout modifying existing segment making machinery.

The additive may be incorporated into the segment in any suitablemanner. However, preferably the additive is incorporated into thesegment by spraying the additive onto the filtration material when thesegment is being formed. For example, the filtration material may be acontinuous band of fibres, which are bundled together to form thesegment, and the additive may be sprayed onto these fibres.

The one or more wrappers circumscribing the segment have a basis weightgreater than about 50 grams per square metre (gm⁻²). It has been foundthat this provides a desired firmness for the mouthpiece. Preferably,the one or more wrappers have a basis weight less than about 100 gm⁻².It has been noted that such a value can provide a good balance betweenfirmness and still allowing the one or more wrappers to be relativelystraightforward to handle during manufacture.

More preferably, the one or more wrappers have a basis weight betweenabout 65 gm⁻² and about 85 gm⁻². Even more preferably, the one or morewrappers have a basis weight between about 70 gm⁻² and about 80 gm⁻². Inpreferred embodiments, a single wrapper is provided and this singlewrapper has a basis weight as set out above. Alternatively, in someembodiments, multiple wrappers may be provided, and the combined basisweight of the multiple wrappers may be the basis weight as set outabove. Preferably, the one or more wrappers comprise a first wrapperhaving a basis weight as set out above, the first wrapper being indirect abutment with the filtration material.

Preferably, the one or more wrappers have a bending stiffness of atleast about 0.08 N in the machine direction of the wrapper. The one ormore wrappers may have a bending stiffness less than about 0.2 N in themachine direction of the wrapper. The machine direction of the wrapperspreferably corresponds to the transverse direction of the smokingarticle.

Preferably, the one or more wrappers have a bending stiffness of atleast about 0.04 N in the cross direction of the wrapper. The one ormore wrappers may have a bending stiffness less than about 0.1 N in thecross direction of the wrapper. The cross direction of the wrapperpreferably corresponds to the longitudinal direction of the smokingarticle.

The term “bending stiffness” used in this specification refers to theresistance of the material to a bending force applied perpendicular tothe plain of the material. The bending stiffness may be determined byInternational Organization for Standardization (ISO) test ISO 5628:2012.

If more than one wrapper is provided, the total bending stiffness in agiven direction of the one or more wrappers is the combined bendingstiffness of the wrappers.

The desired firmness properties that the one or more wrappers help themouthpiece to have may be quantified in terms of a hardness value. Theterm “hardness” used throughout this specification denotes theresistance to deform. Hardness is generally expressed as a percentage.FIG. 1 shows a cigarette 101 before applying a load F and the samecigarette 103 whilst applying load F. The cigarette 101 before load Fhas been applied has a diameter D_(S). The cigarette 103 after applyinga set load for a set duration (but with the load still applied) has a(reduced) diameter D_(d). The depression is d=D_(S)−D_(d). Referring toFIG. 1, hardness is given by:

${{hardness}(\%)} = {\frac{D_{d}}{D_{S}}*100\%}$

where D_(S) is the original (undepressed) cigarette diameter, and D_(d)is the depressed diameter after applying a set load for a set duration.The harder the material, the closer the hardness is to 100%.

As is described in more detail below, and generally known in the art, todetermine the hardness of a portion (such as a filter) of a smokingarticle, smoking articles should be aligned parallel in a plane and thesame portion of each smoking article to be tested should be subjected toa set load for a set duration. This test is performed using a knownDD60A Densimeter device (manufactured and made commercially available byHeinr. Borgwaldt GmbH, Germany), which is fitted with a measuring headfor cigarettes and with a cigarette receptacle.

The load is applied using two load applying cylindrical rods, whichextend across the diameter of all of the smoking articles at once.According to the standard test method for this instrument, the testshould be performed such that twenty contact points occur between thesmoking articles and the load applying cylindrical rods. If the hardnessof a filter or filter portion is being tested then, in some cases, thefilters to be tested may be long enough such that only ten smokingarticles are needed to form twenty contact points, with each smokingarticle contacting both load applying rods (because they are long enoughto extend between the rods). In other cases, if the filters are tooshort to achieve this, then twenty smoking articles should be used toform the twenty contact points, with each smoking article contactingonly one of the load applying rods, as further discussed below.

Two further stationary cylindrical rods are located underneath thesmoking articles, to support the smoking articles and counteract theload applied by each of the load applying cylindrical rods. Such anarrangement is described in more detail below, and shown in FIGS. 5 to7.

For the standard operating procedure for such an apparatus, an overallload of 2 kg is applied for a duration of 20 seconds. After 20 secondshave elapsed (and with the load still being applied to the smokingarticles), the depression in the load applying cylindrical rods isdetermined, and then used to calculate the hardness from the aboveequation. The temperature is kept in the region of 22 degreesCentigrade±2 degrees. The test described above is referred to as theDD60A Test. The DD60A Test and corresponding apparatus are described inmore detail below in relation to FIGS. 5 to 7. The standard way tomeasure the filter hardness is when the smoking article is unsmoked.

Preferably, the hardness of the segment is at least about 75%, morepreferably at least about 80%, and even more preferably at least about85%. Preferably, the hardness of the segment is less than about 100%,more preferably less than about 95%, and even more preferably less thanabout 94%. This can provide a mouthpiece with a satisfactory firmnessfor the consumer.

The desired firmness properties that the one or more wrappers help themouthpiece to have may be quantified in terms of an ovality value. Theterm “ovality” used throughout this specification denotes the degree ofdeviation from a perfect circle. Ovality is generally expressed as apercentage. FIG. 2 shows a perfect circle. In FIG. 2, dimensiona=dimension b, since both dimensions are equal to the diameter of thecircle. FIG. 3 shows an oval. In FIG. 3, dimension a≠dimension b.Referring to FIGS. 2 and 3, ovality is given by:

${{ovality}(\%)} = {\frac{2\left( {a - b} \right)}{a + b}*100\%}$

where a is the largest external diameter of the oval or circle and b isthe smallest external diameter of the oval or circle. In the case of anoval or ellipse, a is the major axis of the ellipse, and b is the minoraxis of the ellipse. Since a=b in a perfect circle, the ovality of aperfect circle is equal to 0%.

To determine the ovality of a portion (such as a filter) of a smokingarticle in accordance with the present invention, the mouth end isviewed along the longitudinal direction of the smoking article. Forexample, the smoking article may be positioned on the mouth end on atransparent stage, so that an image of the mouth end of the smokingarticle is recorded by a suitable imaging device located below thestage.

To simulate the smoking of a smoking article, the smoking article issubjected to a standard smoking test under ISO conditions (35 ml puffslasting 2 seconds each, with puffs occurring once every 60 seconds) asset out in ISO 4387:2000. In the ISO test method, the smoking article issmoked with the ventilation zone fully uncovered. Where it is necessaryto measure the ovality after deformation tests performed both before andafter smoking, two samples of smoking articles having the same designshould be used. That is, non-deformed unsmoked smoking articles shouldbe used for the pre-smoking deformation tests, and non-deformed smokingarticles having the same design are subjected to the smoking test andused for the post-smoking deformation tests.

It is preferable that the mouth end has a low ovality after deformation.Thus, preferably, the ovality of the furthest downstream end of thesmoking article, after a 50% deformation of the furthest downstream endof the smoking article, is less than about 25%.

Moreover, it is preferable that the mouth end return to as close tocircular as possible after deformation, even after smoking. Thus,preferably, the ovality of the furthest downstream end of the smokingarticle, after a 50% deformation of the furthest downstream end of thesmoking article, performed after the smoking article has been subjectedto a smoking test (as described above), is less than about 25%.

Preferably the one or more wrappers have a combined thickness of betweenabout 100 μm and about 210 μm, more preferably between about 120 μm andabout 180 μm. In some preferred embodiments, the one or more wrapperscomprise a first wrapper having a thickness of between about 90 μm andabout 120 μm, preferably about 100 μm. Alternatively or additionally,preferably the one or more wrappers comprise a second wrapper having athickness of between about 30 μm and about 70 μm, preferably about 40μm. Preferably, the first wrapper is adjacent to the segment comprisingpolylactic acid, and preferably the first wrapper extends along theentire length of the mouthpiece. Preferably, the second wrappercircumscribes the first wrapper and connects the mouthpiece to theaerosol generating substrate.

The one or more wrappers may comprise any suitable material orcombination of materials. Examples of suitable materials include, butare not limited to, cellulose based materials, paper, cardboard, recon,cellulose based film, and combinations thereof. The one or more wrappersmay be printed, embossed, debossed or otherwise embellished withmanufacturer or brand logos, trade marks, slogans and other consumerinformation and indicia. Preferably, the one or more wrappers comprisepaper.

Any suitable arrangement of wrappers may be provided. For example, themouthpiece may comprise multiple segments each with their own wrapper,and a combining wrapper circumscribing the multiple segments.Alternatively or additionally, the one or more wrappers may include atipping paper circumscribing the segment and the mouthpiece, andconnecting the mouthpiece to the aerosol generating substrate. Inpreferred embodiments, the one or more wrappers is a single wrapperwhich circumscribes the entire length of the mouthpiece, and a tippingpaper further circumscribes the single wrapper to connect the mouthpieceto the aerosol generating substrate. In such embodiments, the singlewrapper preferably has the basis weight and thickness features describedabove in respect of the one or more wrappers.

Preferably, the one or more filter wrappers have low porosity.Preferably, the one or more filter wrappers have a porosity of less thanabout 1000 Coresta units, more preferably less than about 500 Corestaunits, and even more preferably less than about 100 Coresta units. Theporosity may be as low as 100 Coresta units or lower, or 20 Corestaunits or lower. In addition, or in the alternative, the porosity may bemore than about 1 Coresta unit.

The mouthpiece may have any suitable construction. In some preferredembodiments, the only filter segment in the mouthpiece is the segmentcomprising polylactic acid. Therefore, preferably, no additionalsegments are provided either upstream or downstream of the segmentcomprising polylactic acid. Alternatively, in some other preferredembodiments, the mouthpiece comprises one or more additional segmentsupstream or downstream of the segment comprising polylactic acid. Thus,exemplary mouthpiece structures that may be used include, but are notlimited to, a mono filter, a dual filter, a triple filter, a single ormulti cavity filter, and combinations thereof.

If the mouthpiece comprises a multi component mouthpiece comprising aplurality of segments, the one or more wrappers may surround one, someor all of the segments. Preferably, each segment comprises a respectivewrapper and the whole filter is surrounded by a further wrapper,combining the segments together.

Mouthpieces according to the disclosure can be attached to a tobacco rodto form all or at least part of a smoking article. Preferably, themouthpiece is axially aligned with the tobacco rod. In many embodiments,the mouthpiece is joined to the tobacco rod with tipping paper.

In some embodiments, the smoking article is a conventional cigarette inwhich the aerosol generating substrate is provided in the form of acylindrical tobacco rod, and in which the mouthpiece includes a filter.Alternatively, the smoking article may be one in which an aerosolforming substrate, such as tobacco, is heated rather than combusted, orone in which a nicotine-containing aerosol is generated from a tobaccomaterial, tobacco extract, or other nicotine source, without combustion,and in some cases without heating, for example through a chemicalreaction.

The term “phenols” refers to a class of chemical compounds consisting ofa hydroxyl group (—OH) bonded directly to an aromatic hydrocarbon group.The phenol group includes phenol, catechol, m+P cresols, and o-cresol.

The term “additive for reducing phenols” refers to any additive, whichwhen added to a mouthpiece for a smoking article, is capable of reducingthe level of at least one of phenol, catechol, m+P cresols, and o-cresolin the smoke, when subjected to standard smoking test.

The terms “upstream” and “downstream” refer to relative positions ofelements of the smoking article or filter described in relation to thedirection of mainstream smoke as it is drawn from the aerosol generatingsubstrate and through the filter or mouthpiece.

Features and advantages described in relation to one aspect of theinvention may also be applicable to another aspect of the invention.

The invention will be further described, by way of example only, withreference to the accompanying drawings in which:

FIG. 1 illustrates the definition of hardness;

FIG. 2 illustrates the definition of ovality, using a perfect circle;

FIG. 3 illustrates the definition of ovality, using an oval;

FIG. 4 shows an unwrapped smoking article in accordance with a firstembodiment of the present invention;

FIG. 5 illustrates a perspective view of an apparatus for determiningthe hardness of a filter or a smoking article, in a first configuration;

FIG. 6 illustrates a side view of the apparatus of FIG. 5, in a firstconfiguration;

FIG. 7 illustrates a side view of the apparatus of FIG. 5, in a secondconfiguration;

The filter cigarette 10 shown in FIG. 4 comprises a wrapped rod 12 oftobacco cut filler which is attached at one end to an axially alignedfilter 14 in accordance with the present invention. The filter 14comprises a single segment 16 of filtration material, the filtrationmaterial comprising fibres formed from a blend of about 85% by weightpolylactic acid, 10% by weight polyglicolic acid, and 5% by weightpoly-(L)-lactic acid. The segment 16 also comprises an additive forreducing phenols in the smoke produced by the tobacco rod 12. Thesegment of filtration material 16 is circumscribed by a plug wrap 18,having a basis weight of about 78 grams per square metre. The wrappedtobacco rod 12 and the filter 14 are joined by a band 20 of tippingpaper, which circumscribes the entire length of the filter 14 and anadjacent portion of the wrapped tobacco rod 12.

Six different sample filters were constructed with the filtrationmaterials shown in Tables 1 and 2 below. The filters were attached totobacco rods to form smoking articles and the smoking articles weresubjected to a standard smoking test under ISO conditions (35 ml puffslasting 2 seconds each, with puffs occurring once every 60 seconds) asset out in ISO 4387:2000. In the ISO test method, the smoking article issmoked with the ventilation zone fully uncovered. The delivery levels ofcertain phenols for each smoking article were measured. Tables 1 and 2show the delivery levels of these smoke constituents per milligram ofnicotine delivery, for each of the six different sample smokingarticles.

TABLE 1 PLA Fibres + 10% Smoke constituent Reference Polylactic Mixture(of 96-98% normalized to Cellulose Acid (PLA) triacetin + 2-4% milligram(mg) of Acetate Fibres + Fibres + PLA Fibres + cellulose acetatenicotine 7% Triacetin Noadditive 10% Triacetin flakes) Phenol (μg) 10.8727.20 14.92 11.82 m cresols (μg) 2.43 4.53 2.94 2.54 p cresols (μg) 6.0411.68 7.32 6.44 o-cresol (μg) 2.87 6.25 3.35 2.64

TABLE 2 Smoke constituent Reference normalized to Cellulose PolylacticAcid PLA Fibres + milligram (mg) of Acetate Fibres + (PLA) Fibres + PLAFibres + 10% Triethyl nicotine 7% Triacetin No additive 10% PEG400Citrate Phenol (μg) 10.87 27.20 10.28 6.90 m cresols (μg) 2.43 4.53 2.481.72 p cresols (μg) 6.04 11.68 6.29 4.36 o-cresol (μg) 2.87 6.25 2.671.49

As can be seen from Tables 1 and 2, the filter having polylactic acid(PLA) fibres with no additive delivered a noticeably higher amount ofphenols than the reference standard cellulose acetate filter. However,the filters having polylactic acid with an additive delivered acomparable or lower amount of phenols than the reference standardcellulose acetate filter.

FIGS. 5, 6 and 7 depict an apparatus for testing the hardness of smokingarticles filters.

The apparatus may be a known DD60A Densimeter (manufactured and madecommercially available by Heinr. Borgwaldt GmbH, Germany) device, whichis fitted with a measuring head for cigarettes and with a cigarettereceptacle. As described in more detail below, the hardness of samplescan be tested by following the method which is recommended for the knownDD60A Densimeter device (manufactured and made commercially available byHeinr. Borgwaldt GmbH, Germany). That is, a sample of smoking articlesis held in parallel alignment, and subjected to an overall load of 2 kg,for a period of 20 seconds, and the diameters of the smoking articlesbefore and after compression are recorded. The depression is used todetermine the hardness (%) of each smoking article.

FIG. 5 is a perspective view of an apparatus 4, such as a DD60ADensimeter device, for determining the hardness of a filter of a smokingarticle. The apparatus includes two parallel load applying rods 24positioned over a support plate 30. The support plate 30 includes twoparallel, spaced apart walls 12, with each wall 12 having ten equallyspaced recesses. The recesses are arranged to prevent the smokingarticles 10 from contacting one another during testing.

As can be seen in FIG. 5, ten identically designed smoking articles 10are aligned parallel in a plane, and placed on underlying cylindricalrods 14. The smoking articles 10 extend between corresponding recessesin the walls 12 to hold the smoking articles in place. The underlyingcylindrical rods 14 extend parallel to the walls 12. Each smokingarticle 10 contacts the underlying rods 14 at two points, making fortwenty total points of contact between the smoking articles to be testedand the underlying rods 14.

To test the hardness of a smoking article's filter, the smoking articlesshould be positioned such that the portion of the filter to be tested isin contact with the underlying rods 14. If filter is too short and theportion of the filter to be tested either does not contact both rods orcontacts the rods very close to the ends of the portion of the filter tobe tested, then it would be appreciated that this could be achieved byusing twenty cigarettes in a back-to-back configuration, such as thatshown in FIG. 6.

As shown, the concept of the DD60A Test is that the underlyingcylindrical rods contact the sample material to be tested at twentycontact points. If the filter is sufficiently long to extend across theunderlying rods, then the twenty contact points can be provided with tensamples (as shown in FIG. 5). If the filter is not sufficiently long,then the twenty contact points can be provided with twenty samples, asshown in FIG. 6.

As can be seen in FIG. 6, portions of the tobacco rods have been removedfrom each smoking article 10, and the filter portion of each smokingarticle 10 rests on a respective cylindrical rod 14. In FIG. 6, thehardness of the mouth end segment is being tested, and therefore it isthis portion of the filter which rests on the rod 14, and the mouth endsegment is approximately centered on the rods 14. If necessary, the tipsof the smoking articles extending away from the cylindrical rods 14 maybe supported by an underlying supporting means to prevent pivoting ofthe smoking articles.

The apparatus is shown in FIG. 6 in a first configuration, in which thetwo load applying cylindrical rods 24 are raised above and out ofcontact from the smoking articles 10. To test the hardness of thesmoking articles, the load applying cylindrical rods 24 are lowered to asecond configuration, to come into contact with the smoking articles 10,as shown in FIG. 7. When in contact with the smoking articles 10, theload applying rods 24 impart an overall load of 2 kg across the twentycontact points of the smoking articles 10 for a duration of 20 seconds.After 20 seconds have elapsed (and with the load still being applied tothe smoking articles), the depression in the load applying cylindricalrods 24 across the smoking articles is determined, and then used tocalculate the hardness.

1. A smoking article comprising: an aerosol generating substrate; and amouthpiece attached to the aerosol generating substrate, the mouthpiececomprising a segment comprising: a filtration material comprising agathered sheet of material comprising polylactic acid; wherein themouthpiece further comprises one or more wrappers circumscribing thesegment, the one or more wrappers have a combined basis weight of atleast about 50 grams per square metre (gm⁻²).
 2. A smoking articleaccording to claim 1 wherein the segment further comprises an additivefor reducing phenols.
 3. (canceled)
 4. A smoking article according toclaim 1, wherein the filtration material comprises a blend of polylacticacid and at least one other polymer.
 5. A smoking article according toclaim 4, wherein the blend comprises a blend of polylactic acid,polyglicolic acid and poly-(L)-lactic acid.
 6. A smoking articleaccording to claim 2, wherein the additive for reducing phenols isdispersed amongst the filtration material.
 7. A smoking articleaccording to claim 2, wherein the additive for reducing phenols is theonly additive provided in the segment.
 8. A smoking article according toclaim 1, wherein the one or more wrappers comprise a first wrapper, thefirst wrapper being in direct abutment with the filtration material andhaving a basis weight of at least about 50 grams per square metre(gm⁻²).
 9. A smoking article according to claim 1, wherein themouthpiece segment has a hardness of at least about 75%.
 10. A smokingarticle according to claim 1, wherein the mouthpiece segment has anovality, after a 50% deformation of the mouthpiece segment, of less thanabout 25%.
 11. A smoking article according to claim 1, wherein the oneor more wrappers have a combined thickness of at least about 80 μm. 12.A smoking article according to claim 1, wherein the one or more wrappershave a combined bending stiffness of at least about 0.08 N in themachine direction of the wrapper.
 13. A mouthpiece for a smokingarticle, the mouthpiece comprising: a segment comprising: a filtrationmaterial comprising a gathered sheet of material comprising polylacticacid; wherein the mouthpiece further comprises one or more wrapperscircumscribing the segment, the one or more wrappers have a combinedbasis weight of at least about 50 grams per square metre (gm⁻²).
 14. Amouthpiece according to claim 16, wherein the blend comprises a blend ofpolylactic acid, polyglicolic acid and poly-(L)-lactic acid.
 15. Amouthpiece according to claim 13, wherein the one or more wrapperscomprise a first wrapper, the first wrapper being in direct abutmentwith the filtration material and having a basis weight of at least about50 grams per square metre (gm⁻²).
 16. A mouthpiece according to claim13, wherein the filtration material comprises a blend of polylactic acidand at least one other polymer.
 17. A mouthpiece according to claim 13,wherein the segment further comprises an additive for reducing phenols.18. A mouthpiece according to claim 17, wherein the additive forreducing phenols is dispersed amongst the filtration material.
 19. Amouthpiece according to claim 17, wherein the additive for reducingphenols is the only additive provided in the segment.